We’re a funny little species, valuing one thing just because there’s less of it than some bunch of other things. Like the Nintendo Entertainment System game Nintendo World Championships, manufactured for a contest with that same name and held back in 1990. Copies of the game have sold for over $20,000. Nintendo made 116 in all for its one-time competition: 90 gray and 26 gold (like the original Legend of Zelda cart). Then it zipped around the U.S., touring 29 cities and bidding gamers compete by playing its selections, plucked from three NES games — Rad Racer, Super Mario Bros. and Tetris — while on a timer that topped out at 6 minutes, 21 seconds. And there may be a legitimate gray-edition copy for sale right now on eBay, a copy that’s pushing $6,000 in bids as of Friday morning. It’s not a very nice-looking copy — the sticker’s been abraded off for some reason, and NES carts were never pretty things to begin with. I say “may be a legitimate copy” because this is one of those things where counterfeits, i.e. “reproduction carts,” aren’t uncommon. The auctioneer claims it’s legit, of course, adding: This is known as the infamous “Mario” NWC cart that someone probably wrote on there long ago not having a clue what they actually had. Still, case in point, this is an authentic, original NWC cart from the championship back in the early 90s. The cart plays just fine and may some day be worth much more if someone decides to investigate a forensics lab’s involvement to see if they can determine the official number by running tests on the cart. The number the auctioneer’s referring to would have been in the upper left corner of the sticker. Wikipedia has a shot of this here, though don’t ask me why it reads “0260″ when Nintendo only made 116.